Nazi Germany was a police state, increasingly under the control of Himmler and his henchman Heydrich, but it was an understaffed one. The twenty-two Gestapo officials in Würzburg, for example, were responsible for the entire population of Lower Franconia, which numbered more than 840,000 in 1939. The town of Krefeld was more closely supervised; around 170,000 people lived there, under the watchful eye of between twelve and fourteen Gestapo officers. In both towns, the Gestapo had to rely heavily on local people for tip-offs about breaches of the law. The surviving police files reveal that these were not in short supply. Of the eighty-four cases of ‘racial defilement’ investigated in Würzburg between 1933 and 1945, forty-five – more than half – originated with a denunciation from a member of the public. The character of these denunciations sheds vital light on popular attitudes towards the ‘Jewish Question’. A Jewish man and an Aryan woman were arrested because the woman’s estranged husband alleged they were having a sexual relationship; their accuser’s main motive seems to have been to get rid of his wife, but her alleged lover committed suicide in custody. An apparently mixed couple having a drink together were reported to the Gestapo because the man was blond-haired (both parties were in fact Jewish, so no charge could be pressed). In Krefeld the Gestapo were able to be more active: the proportion of cases involving Jews rose sharply from less than 10 per cent before 1936 to around 30 thereafter. Of these cases, some 16 per cent were decided by the courts; in over two-fifths of cases, however, the Gestapo sent the individuals concerned to concentration camps or imposed ‘protective custody’. Yet even in Krefeld more than two-fifths of the cases brought against Jews before the war were initiated by denunciations, a much higher proportion than for other cases, suggesting that denunciation was disproportionately directed against Jews.

Does this confirm the thesis that most ordinary Germans were anti-Semites? No. At most, denouncers amounted to just 2 per cent of the population. What it does suggest is that anti-Semitic legislation was a powerful weapon in the hands of a minority of Germans: the morally vacuous lawyers who drafted and implemented it, the Gestapo zealots who enforced it, and the odious sneaks who supplied the Gestapo with incriminating information. There was one major stumbling block for this unholy trinity, however. The legacy of decades of intermarriage between Jews and Gentiles [more than in any other country] was a substantial group of people who defied clear-cut racial categorization because they had only one Jewish parent, or fewer than four Jewish grandparents. Were they Jews?

In any one-party state, laws become something you enforce against your enemies and ignore among friends.